Thread-cutting mechanism for sewing-machines.



E. B. ALLEN & J. C. RINGE.

THREAD CUTTING MEGHANISM PoR SEWING MACHINES.

l APPLICATION FILED JUNE 17, 1909. 1,028,655. Patented June 4, 1912.

hun@I MQW coLUMDlA PLANOGRAPH C0.. WASHINGTON, n. c.

ZI-Ventura? lE. B. ALLEN & J. G. RINGE. THREAD CUTTING MECHANISM FOB. SEWING MACHINES.

APPLICATION FILED JUNE 17, 1909. I

COLUMBIA PLANUGRAPH cu.. wAsmNa'ww. n

' ceri EDWARD B. ALLEN AND JOI-IN C. RINGE, OF IBRIIDGEPORT, CONNECTICUT, ASSIGNORS TO THE SINGER MANUFACTURING COMPANY, A CORPORATION OF NEW JERSEY.

THREAD-CUTTING MECHANISM FOR SEWING-MACHINES.

Loeaeee.

Specication of Letters Patent.

Patented June 4f, 1912.

Original application led August 7, 1908, Serial No. 447,381. Divided and this application filed June 17,

To all 'whom t may concern Be it known that we, EDWARD B. ALLEN and JOHN C. RINGE, citizensy of the United States, residing at Bridgeport, in the county 5 of Fairfield and State of Connecticut, havev invented certain new and useful Improvements in Thread-Cutting Mechanism for Sewing-Machines, of which the following is a specification, reference being had therein to the accompanying drawings.

This application is a division of our pending application Serial No. 447,381, filed August 7, 1908, and the present invention has for its object to provide a purl-thread guide which shall accommodate itself to overseaming stitch-forming mechanism for changes in the direction of feed, as 1n buttonhole stitching machines and embroidering machines wherein the stitching mechanism is 2 0 mounted independently of the feeding mechanism and does not follow changes of direction of the latter. l

The present invention is designed espencially for embodiment in straight buttonhole stitching machines of the class exemplified in that forming the subject of the UnitedStates patent of Edward B. Allen No. 806,231, dated December 5, 1905, al-

' nthough adapted for'use in other types of machines.

being held in a traveling clamp to which is imparted alternate advance and retrograde step-by-step feeding movements to space the stitches, intermediate dwells for the production of barring stitches at opposite ends of the buttonhole, and lateral shifting movements for properly positioning the edgecovering and barring stitches in a manner p lwell-known. According to the present improvement, in .its preferred form, a purlthreador cord-guide is mounted upon an oscillating carrier journaled substantially concentrically with the needle-bar and is so controlled that its delivery eye is maintained in advance of the stitching mechanism during the stitching of the first side of the buttonhole, and is then thrown to the side of the stitching mechanism for the first barring operation, after which it is shifted to a position diametrically opposite its initial position in relation to the stitch-forming mechanism which it maintains during the stitching of the second side of the buttonhole and the barring of the'second end, after which both' the needle-thread andthe purl-thread are severed by a common cutting implement in the present instance carried -by the clamping foot of the workholder. By maintaining the puri-thread guide in4 advance of t-he stitch-forining mechanism throughout both t-he advance and retrograde feeding movements, the purl-thread is adapted to be laid upon the work where it is stitched in place and embraced by the side overseam stitches, while the lateral deflection of the purl-thread at the end of the first side' stitching operation permits the laying of a succession'of bar stitches and the secure anchorage of the last side-overseain-stitch in line with the center of the buttonhole slit so that in the subsequent reversal of the position of the threadguide the last o verseam stitch of the first side aords a firm turning point for the `purl-thread or cord so that the lead of the latter will be within the field of operation of the stitch-forming mechanism in beginning the overseaming of the second side of the buttonhole. A similar deflection of the purl-thread is not required at the initial end of the buttonhole, for the reason that means are provided in practice for'severing such thread at the completion of the stitching operation.

One of the difliculties heretofore experienced in the handling of a purl-thread or cord has been the cutting of the same in conjunction with the stitching thread at the completion of a stitching operation. 'According to the present improvement, it is proposed to employ thread-cutting mechanisni similar to that of the Allen Patent No. 885,310, dated April 21, v1908, but with the upper cutting mechanism adapted for accommodating the two sizes of threads used in stitching providing the purl, both of which threads are at the end of each stitching operation out and nipped preparatory to the succeeding stitching. operation. According to the present improvement, the upper work-clamping foot is'provided with a rigid and a yielding nipping jaw and the spring nipping blade with a thread-separating finger whereby the stitching thread is by reference to the accompanying drawings,`

in which- Figure 1 is a rear side elevation, partly- Y in section, of`a straight button-hole stitching machine of the well-known `Singer No. 71 class, embodying the present improvements, and Fig. 2 is a lbottom plan view of the same. Fig. 3 is a sectional plan of the machine with the bracket-arm removed to expose the mechanism beneath. Fig. 4 is a perspective view of the purling mechanism, and Fig. 5 a similar view of a portion thereof taken from a different position. Fig. 6 is a rear end View of the forward portion of the operating mechanism of the .purlthread guide. Fig. 7 is a bottom plan of the clamping foot of the work-holder with the removable section omitted to expose the cutting and nipping devices, and Fig. 8 a sectional elevation of the same. Fig. 9 is a perspective view, upon an enlarged scale,

of the yielding thread-nipping jaw, and Fig. 10 a similar view of the thrust member 112 and swinging plate 114.

The machine is constructed with the usual bed-plate 1 and overhanging bracket-arm 2 in which is journaled the main-shaft 3 operatively connected at its forward end with the needle-bar 4 having the thread-carrying needle 5.

As in the said Patent No. 806,231, the swinging needle-frame 6 derives its lateral movements, which are communicated to the n eedle-bar and needle, through a pitman connection 7, rocker 8 and link-bar 9 to which latter are communicated endwise reciprocating movements for imparting to the needle its side-stitch and bar-stitch jogging movements, and sidewise movements to effect the coupling of said bar alternately to different points of its swinging actuator. The depending rearwardly extending tail 10 of this link-bar is adapted in its lateral movements to engage the upper end of a laterally toothedV coupling lever 11 fulcrumed at 12 to the lower section 13 of an eccentric-rod whose upper section 14 is slidingly fitted to the lower section 13 and normally coupled thereto by means of the coupling lever'll. When the link-bar 9 is in side-stitching position the tail 10 is disengaged from the coupling lever 11, but when the link-bar is in barring position the tail 10 serves to shift the coupling lever 11 to uncouple the sections 13 and 14 of the eccentric-rod to enable the latter to reciprocate idly.

-'llh'ewlower end of the eccentric-rod section 13 'is pivotally connected with a lateral arm 15 of a rocker 16 having a depending upon one arm of a bellcrank-lever whoseY other arm 24 is connected by means of a pitman 25 through the slide-block 26 with the clamp base-plate 27 from ywhich the advance and retrograde step-by-step feeding movements are imparted to the work-clamp; and the cam-wheel 22 has a second camgroove 28 entered by a stud carried by the rock-lever 29 fulcrumed at 30 and having its opposite end connected by means of a screw 31 with the slide-plate 32 of the workholder, whereby the lateral shifting movements are communicated to the work-holder.

The upper side-plate of the work-holder is provided with'bearing lugs 33- to which are pivotally connected by means of the pin 34 the depending lugs 35 of the upper.

clamp-lever 36 carrying the clamping foot 37 with lower serrated bearing portion entering and normally seated upon the bottom ofthe recess 38 formed inthe top of the slide-plate v32.

As herein represented, Yan oscillating shuttle within the shuttle race 39 coperates with the needle in the production of oversea'm stitches. Y.

Secured to the lower end of the head of the bracket-armx2 is a bearing plate 40 parallel with the bed-plate and formed with an opening 41 surrounding the needle-bar to which is fitted the hub 42 of a segmental pinion 43 having an annular notch near its upper end entered by the inner edge of the sectional thrust-plate 44 secured upon the bearing plate 40 by means of screws 45.

The purl-thread guide is formed with a laterally offset shank 46 secured at its upper end by means of fastening screws 47 to the pinion 43 and has near its lower end a thread aperture 48 forming the mouth of a thread channel 49 extending downwardly through the contracted lower portion 50 of the thread-guide and terminating in a delivery opening at the lower end of the same. As will be observed, the' oscillation of the pinion 43 by means about to be described causes the purl-thread guide to assume posiis a rocking plate 52 having a segmental se-l ries 'of gear teeth 53 meshing with the teeth of the pinion'43, and adapted to oscillate the same. At one side of the fulcrum-screw 51 the rocking plate 52 is provided with a perforated ear 54 embraced by the forked head 55 of a sectional connecting rod pivotally attached thereto by means of a screw-pin 56. The rod 57 to which the head 55 is connect* ed, is formed at its rearward end with a fixed collar 58 fitted within the tubular section 59 and having interposed between the same and the forward end of t-he cavity in t-he section 59 the spring` 60, whereby the sectional rod is normally maintained in contracted condition, with the collar 58 firmly seated upon the threaded bushing 61 entering the rearward end of the section 59 and having a rearwardly extending lug 62 secured by means of screws 63 to thel face of a slot-ted slide-plate 64 whose rectangular central opening 65 embraces a guide-block 66 fitted upon the upright shaft 67 of the feed-wheel 22.

The slide-plate 64 rests upon and is supported by the pattern-cam 68 fixed upon the feed cam-shaft 67, and has a depending lug 69 normally resting upon the plural-stepped operative edge of the cam 68 and constituting a follower therefor, being maintained in yielding` contact therewith by means of a spring 70 interposed between a stud 71 upon the lug 62 and a stud 72 upon the lower end of the head of the bracket-arm. The slideplate 64 is confined upon the upper face of the cam 68 by means of a disk 7 3 whose hub is iiXed upon the feed cam-shaft 67. As indicated more particularly in Figs. 3 and 5, the cam 68 is of lgeneral snail-shape with three steps at one side formed by two adjacent notches 74 and '75, which afford an inner, an outer and an intermediate step which the lug 69 is caused tosuccessively engage under the action of the spring 79 in the rotation of the cam 68.

T he positions of the parts represented in Figs. 1 to 4 inclusive, are those assumed immediately after the first barring operation and while the second side ofthe buttonhole isbeing stitched, whereby the delivery end of the purl-thread guide is shifted into a position in front'of the needle by the action of the spring 70 upon the slide-plate 64, the lng 69 having rested upon the outer periphery or portion a of larger curvature of the cam 68 as represented in Fig. 5 duringthe stitching of the first side of the buttonhole and entered the notch 74 so as to rest upon the intermediate step for the first barring operation and entered the second notch 75 so as to rest upon the step c at the completion of the barring operation for the stitching of the second side of the buttonhole.

As the purl thread-guide 46 has an oscillatory movement around the needle-path, it will be seen that when the lug 69 of the slide-plate 64 rests upon the step b of the pat- -tern-'cam 68, the thread-guide delivery opening 50 assumes a position at one side of the stitch-forming mechanism and intermediate its eXtreme positions upon opposite sides of the needle which it occupies in the respective side stitching operations of the machine; and this intermediate position is assumed while the longitudinal feeding mechanism is inactive and. the barring is being done inter-A mediate the lateral movements of the work for spacing the lines of side stitches upon opposite margins of the buttonhole slit.

As the section 59 of the eXtensible connecting rod immediately begins its retractil@ movement under the action of the eccentric portion c of the pattern-cam during the stitching of the second side of the buttonhole, it is necessary to forcibly detain the purl-thread guide in its third or eXtreme position to prevent its premature return to initial position. To this end. the rocking plate 52 is formed in its upper'side with a notch 76 entered by the ratchet shaped tooth 7 7 of a detent block 78 iixedupon the free end of the flat spring 79 which is secured at its opposite end by means of fastening screws 80 upon the top of the bearing plate 40. As the plate 52 carrying the toothed sector 53 is rocked to bring the thread-guide into extreme position, the tooth 77 of the detent snaps into the notch 7 6 of said plate and detains the same while the section 59 of the connecting rod is gradually retracted and the spring 6() is correspondingly com pressed by the distention of the component members of the connecting rod between which it is interposed. The detent block 7 8 is provided with an overhanging lug 81 carrying an adjustable stud-screw 82 with locknut 88, the lower end of the stud-screw being engaged at the completion of each stitching operation by the operating crank-arm ,84 fixed upon one end of the tension release rock-shaft 85 having at its opposite end an arm 86 with wedge-shaped outer end 87 'adapted to enter the space between and separate the tension-disks 88 in a manner wellknown. The means for actuating the tension releasing device will be later described in connection with the thread. severing device.

As in the United States patent to Edward B. Allen No. 885,310, the clamping foot, constituting the Lipper member of the workholder, is formed at one side of its forward end with a slot parallel with its upper face, the lower side of which is closed by means of a detachable section 32X, and `iournaled in an upright bearing boss 89 upon the body of the clamping foot is a cutter rock-shaft 90 having fixed upon its lower end by means of a screw 90)c the thread-cuttingblade 91 adapted to eoperate with a cutting edge'92 formed upon the clamping foot section 32X in cutting the threads, and a superposed nipping blade 93 coperating with relatively stationary jaws carried by the body o f the foot and disposed at different distances from one of the extremities of the blade 93 relative to the length o-f the latter in nipping the threads. The operative edge of the nipping blade is providedin its outer portion with two thread-receiving notches 94 and 95 with an intermediate spur or 'threaddividing finger 96 for separating the needlethread and purl-thread at the completion of a stitching operation. The bottom of the foot-portion 32 is formed immediately above the path of movement of the thread-notch 94 with a rigid flat seat operating in conjunction with the adjacent upper face of the thread-nipping blade to nip the needlethread, and adjacent said seat and upon the same side of the nipping blade 93 the footportion 32 is recessed to receive a yielding` seat or jaw 97 in the form of a block whose thin shank 98 is set into the top of the foot 32 and secured therein by means of a fastening screw 99, the shank 98 being sufficiently thin and elastic to permit the block 97 to yield upwardly slightly to accommodate the nipping device to the larger purl-thread preferably employed in the working of buttonholes. 'As represented in Fig. 7, the operative corner of the block 97 is notched or recessed toinsure the proper location of the pivotally connected the forward end of a slide-rod 102 whose rearward end is supported within a bearing 103 mounted upon the upper work-clamp lever 3G and provided upon opposite sides thereof with the spaced fixed collars 104 and 105. A spring 106 intermediate a perforated lug 107 of the bearing 103 and a lateral pin 108 upon the collar 109 fixed upon the forward portion of the rod 102 serves to yieldingly maintain the rod in retracted position with its fixed collar 105 resting against the forward face of the bearing 103, and the nipping and cuting blades in advance or operative position. A rock-shaft 110 mounted in a bearing bracket 111, fixed to the bracket-arm, carries at its forward end a rigid lateral arm 112 upon which is pivotally mountedby means of the screw'113 the thrust-plate 114 yieldingly maintained in normal alinement with said arm by means of a spring 115 and a igstaf thrust-plate 114 which snaps in behind it,

so that upon Vthe return of the clamp wit-h the rod 102, the latter is detained while its carrying clamp member 36 continues its return, thereby slowly turning the cutter rockshaft 90 and opening the nipping device to release thc threads nipped at the end of the previous stitching operation to enable them to be stitched into the goods in the final barring operation.

The rock-shaft is provided upon its rearward end with a lateral arm 117 having an axially yielding stud 118 adapted to engage the-top of the lug 119 carried by the collar 120 of the plunger-rod 121 mounted in the stop-lever 122 and normally forced upwardly by means of the spring 123 in contact with the stopping cam 124 when the stop-lever 122 is thrown into operative relation with said stopping cam at the completion of a stitching operation. When the stop-lever 122 is thrown backwardly into operative position, the lug 119 first forces the stud 118 backwardly, but the depression of the plunger-rod 121 by the cam 124 carries the collar 120 downwardly sufficiently to permit the stud 118 to snap over the top of the lug 119 when the rise of the plungerrod 120 as its upper end enters the usual notch in the stopping cam 124 causes the engagement of the lug 119 with the stud 118, thereby lifting the arm 117 and correspondingly shifting the arm 112 with its thrustplate 114, which permits the retraction of the rod 102 under the action of its spring 106, thus throwing the cutting and nipping knives 91 and 93 forwardly to successively nip and sever the needle and Apurling threads. When the stopping Ylever 122 is again thrown forwardly in starting the mav chine, the lug 119 is disengaged from the stud 118, and the arm 117 is caused to descend under the action of the spring 125 connecting its outer end with a pin 126 upon the stopping lever, thus depressing the arm 112 and causing the edge of the thrustplate 114 to rest upon the rod 102 of the thread-cutting device, as before described. As before indicated, the cut ends of the threads are held within the nipping device until the stitching of the second side of the succeeding buttonhole has been commenced, when the cutting and nipping blades are gradually retracted to the side of the stitching aperture in the clamping foot until the buttonhole is finished, when the cutting and nipping. operationis repeated as before de.-

scribed.

As represented in Figs. 1, 3 and 6 the Vrock-shaft 110 has fixed to its forward end portion by means of thel stud-screw 127 the hub 12S of a bent arm 129 having a forked forward end 130 adapted to embrace the spherical crank-pin 131 carried by the operating crank-arm 84: of the tension releasing device. It will thus be seen that the rocking of the shaft 110 as described not only causes the actuation of the thread-cutting and nipping devices, but separates the tension-disks 88 and disengages the detent member 7S from the sector-plate 52 to permit the purlthread guiding finger to return to initial position preparatory to the stitching of the first side of a succeeding buttonhole. In practice, the parts are so timed that the thread-cutter is actuated slightly in advance of the return of the purl-thread guide to initial position, which insures the seizure of the purl-thread adjacent the yielding jaw 97 of the nipping device. rIhe blades 91 and 93 are in practice made sufficiently thin to have a slight spring, so that the latter may not crush either the needle-threadv or the purl-thread against their respective fixed nipping jaws in the nipping operation.

The machine represented in the accompanying drawings is provided with the lower thread-cutting and pull-0E device shown in the said United States Patent No.

885,310, but the same is not herein described,v

and forms no part of the present invention.

It will thus be seen that in the machine herein shown and described, the stitch-forming mechanism is of the non-rotary type commonly employed in the stitching of straight-buttonholes, and that the purlthread guide is mounted for circular movement relatively thereto and thus to the lead of the thread through the needle-eye which is always the same regardless vof the movement of the material in opposite directions for spacing the stitches under the action of the feeding mechanism. It will also be seen that the thread-cutting and nipping devices for both the purl-thread and the needlethread, being mounted upon the work-clamp, partake of the feeding movements of the work and thus have a lateral movement relative to the stitch-forming mechanism and to the plane of the jogging movements of the needle, so that these thread-engaging members have a movement, in the cycle of the machine, alternately out. of and into the range of operation of the needle and the purl-threaded guide.

Having thus set forth the nature of the invention, what we claim herein is 1. In a sewing machine, the combination with overseaming stitch-forming mechanism including a thread-carrying needle, and feeding mechanism for moving the work in different directions in relation to the stitch-forming mechanism, of a purl-thread guide, means for maintaining the same in advance of the stitch-forming mechanism with relation to the direction of feed, and means connected with the feeding mechanism and deriving therefrom feeding movements relative to the stitch-forming mechanism whereby both the'needle-thread and the purl-thread are severed at the end of a stitching operation.

2. In a sewing machine, the combination with overseaming stitch-forming mechanism including a thread-carrying needle, and feeding mechanism, of a purl-thread guide coperating with the stitch-forming mechanism-in the-production of a corded overseam, and means including a movable member and a plurality of separate threadengaging shoulders adapted for coperation therewith at different distances from an eX- tremity of its operative portion, whereby the needle-thread and purl-thread respectively, may be successively nipped and severe 3. In a sewing machine, the combination with overseaming stitch-forming mechanism including a thread-carrying needle, and feeding mechanism, of a purl-thread guide cooperating with the stitch-forming mechanism in the production of a corded overseam,and means including a movable member and a plurality of separate threadengaging shoulders upon the` same side thereof and a thread-separating linger intermediate said shoulders for nipping the needleand purl-threads and for severing the same. v

4. In a sewing machine, the combination with overseaming stitch-forming mechanism including a thread-carrying needle,

and feeding mechanism, of a purl-thread guide coperating with the stitch-fo-rming mechanism in the productionl of a corded overseam, and means including a plurality of thread-engaging shoulders of which one is adapted to yield relatively to another for nipping respectively the needleand purlthread and for severing the same.

5. In a sewing machine, the combination with overseaming stitch-forming mechanism including a thread-carrying needle, and feeding mechanism, of a purl-thread guide coperating with the stitch-forming mechanism in the production of a corded overseam, and means including a threadseparating implement adapted to engage upon opposite edges thereof respectively the needle-thread and purl-thread, and a common cutting blade for-severing both the needle-thread and the purl-thread at the end of a stitching operation. l

6. In a sewing machine, the combination with overseaming stitch-forming mechanism including a thread-carrying needle, and feeding mechanism, of a purl-thread guide coperating with the stitch-forming overseam, means for cutting the needleand purl-threads, a common nipping member for engaging both of said threads, and separate nipping members coperating with said common nipping member and each adapted to engage a different one of said threads.

7. In a sewing machine, the combination with overseaming stitch-forming mechanism including a thread-carrying needle, and feeding mechanism, of a purl-thread guide coperating with the stitch-forming mechanism in the production of a corded overseam, means for cutting the needleand purl-threads, and nipping means having operative parts arranged side by side and acting independently upon the respective threads.

8. In a sewing machine, the combination with overseaming stitch-forming mechanism including a thread-carrying needle, and feeding mechanism, of a purl-thread guide coperating with the stitch-forming mechanism in the production of a corded overseam, means for cutting the needleand purl-threads, nipping means acting independently upon the respective threads, and means for directing said threads to their respective nipping means.

9. In a sewing machine, the combination with overseaming stitch-forming mechanism including a thread-carrying needle and feeding mechanism, of a purl-thread guide mounted to maintain during the operation of the feeding mechanism a position in advance of the stitch-forming mechanism relatively to the direction of feed, :nippingv and cutting devices for the needleand purlthreads including a movable nipping jaw and relatively stationary nipping jaws for said threads disposed upon the same side of said movable jaw and o-f which one is adapted to yield relatively to the other, and means for actuating said cutting and nipping devices.

l0. In a sewing machine, the combination with stitch-forming mechanism including a thread-carrying needle, a work-holder, feeding mechanism for imparting feeding movements to the work-holder, and means for producing relative jogging movements between the needle and the work-holder, of a purl-thread guide adapted to cooperate with the stitch-forming mechanism in the production of a corded overseam, and 4means mounted upon and carried by the workholder for independently nipping and cutting the needleand purl-threads at the completion of a stitching operation.

1l. In a sewing machine, the combination with stitch-forming mechanism including a thread-carrying needle, a work-holder, feeding mechanism for imparting feeding movements to the work-holder, and means for producing relative jogging movements between the needle and the work-holder, of a purl-thread guide adapted to coperate with the stitch-forming mechanism in the production of a corded overseam, and means mounted upon and carried by the workholder lfor cutting andnipping the needleand purl-threads, including nipping jaws for the respective threadsV of which one is adapted to yield relatively to the otherand both to act in conjunction with a common nipping blade.

In testimony whereof, we have signed our names to this specification, in the presence of two subscribing witnesses.

EDWARD B. ALLEN. JOI-IN C. RINGE. Witnesses:

, DONALD NOBLE,

Am M. DONIHEE.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents, Washington, D. C. 

